We propose to determine how the chemotactic signal is transmitted to the flagellar machinery, how this signal regulates the frequency of reversal of flagellar rotation, and how membrane components of E. coli convert energy provided to the membrane into flagellar rotation. Using specialized transducing phages and hybrid plasmids produced by recombinant DNA techniques, gene products necessary for motility and chemotaxis were identified and preliminarily localized. Further experiments are designed to identify the remaining fla and che genes and to enhance the expression of gene products normally synthesized at low levels by utilizing cloning vehicles which display increased promotor activity. Other experiments are designed to determine the relationships between these protein and the relationships between these proteins and the basal structure of the flagella organelle. The proteins will be purified and attempts will be made to reconstruct their function in the model systems. On the basis of these experiments, mechanisms will be proposed for the activity of these proteins and genetic and biochemical experiments will be done to test these mechanisms. The goal of this work is to outline all of the steps involved in generating and regulating flagellar rotation. The mechanisms involved in these processes will provide a model for understanding the transmission and integration of sensory signals of more complicated systems.